Spring/Summer 2021 Famously Hot Forecasts

Columbia, SC NATIONAL WEATHER SERVICE Weather Forecast Office NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION FAMOUSLY HOT FORECASTS Spring/Summer 2021 10th Anniversary of the Inside this issue: 2011 “Super Outbreak” 2011 Super Outbreak 1 by Rich Okulski - Meteorologist in Charge Climate “Normals” 5 Virtual Outreach 7 n April 28, 2011 then WFO Memphis Warning Coordination Meteorologist Rich Okulski de- Spring/Summer Hazards 9 O parted his office with fellow manager, Data Acquisi- Tropical Outlook 11 tion Program Manager Zwemer Ingram to survey severe tornado damage in Smithville, Mississippi. Rich River Flooding 12 received a call from Mississippi Emergency Manage- ment Agency coordinator Tracy Pharr while driving COOP Corner 14 across Northern Mississippi. She urgently asked how long it would take them to reach the town. Rich heard the anxiety in her voice and asked whether the damage was “not as bad or worse” than the EF-4 damage tornado in Yazoo City in 2010. She said “worse” with- out hesitation. Rich called his regional headquarters, informed them that Smithville could be a rare EF-5 damage tornado, and asked whether he could make the call at the site. Regional headquarters gave Rich permission to make the call. Rich and Zwemer reacted with both awe and horror as they drove through Smithville on their way to the Incident Command Post. Zwemer immediately thought back to the 1974 Super Outbreak which he lived through as a teenager. Rich thought back to his memories of the bombing damage inflicted on Safwan, Iraq by the U.S. Air Force during the First Gulf War. They spent most of the day surveying incredible tornado damage which both of them hope to never witness again. EF-5 damage to a well-built, anchored home Ford Explorer that was thrown into a water tower in Smithville, MS. NWS Columbia, SC—Spring/Summer 2021 Page 2 Super Outbreak – Continued The most notable damage included the complete destruction of the police station and post office, a Ford Explorer hurled ½ mile into one of the town’s water towers which then caromed another ¼ mile prior to ground impact, a 1965 Chevy pickup which could not be found in town, a house which had two ends still standing but the middle gone, and mangled home appliances. Rich rated the first EF-5 damage tornado in Mississippi since 1966 and the first EF-5 for the 2011 Super Outbreak. Sixteen people lost their lives and another forty were injured. Rich remembered an emergency responder who smoked as she recounted one of Smithville’s tragic stories despite the smell of propane in the air from broken pipes. A babysitter in a well con- structed home died when the violent tornado demolished the structure. She saved the two children in her care by covering them with her body. Emergency responders evacu- ated those children by air to Memphis, because they had been impaled by debris. The situation could have been far worse, however the county emergency manager in coordination with the NWS Memphis office kept students from departing the town’s schools which were not in the tornado’s path. The 2011 Super Outbreak was a once in a generation severe weather event. We must be prepared for the next outbreak of this magnitude through awareness, preparedness, and skilled execution. Our nation’s citizens depend on it. A look at the number of tornadoes from the April 2011 “Super Outbreak” Graphic courtesy of NWS Mobile/Pensacola NWS Columbia, SC—Spring/Summer 2021 Page 3 Advancing Impact-Based Warnings by Chris Landolfi - Meteorologist ational Weather Service offices across the country have been working to devel- N op better impact-based warnings for emergency managers and the general pub- lic for almost ten years, ever since the 2011 tornado season which saw over 550 tornado fatalities. The idea is that not every warning is created equal. Minor roadway flooding does not necessitate a flash flood warning that activates wireless emergency alerts, which are alerts sent directly to mobile phones. Tornadoes and severe thunder- storms also do various degrees of damage. There needs to be a way to distinguish be- tween particularly damaging and dangerous storms from ones that may just barely reach severe limits. Minor Street Flooding (Left) versus 2015 Historic October Flood (Right) Technology has advanced significantly in the past ten years with implementation of dual-polarization radar and so must our warnings. Some degree of impact-based wording has been applied to each severe thunderstorm, tornado, and flash flood warnings. Tornado and flash flood warnings are “tagged” based on their severity: “Base (no tag), Considerable, or Catastrophic (Emergency).” With each higher tag, the wording will be- come more urgent. For example, the words: “You are in a life-threatening situation” and “This is a Particularly Dangerous Situation” will be in the warning text. Beginning this year (expected to be implemented July), severe thunderstorm warnings will also feature a tag: “Base (no tag), Considerable, and Destructive” based on both wind speeds and/or hail size. Storms that are expected to produce 80 mph winds or 2.75 inch hail will activate wireless emergency alerts. Base Considerable Catastrophic (Destructive) Severe 58 mph wind 70 mph wind 80 mph wind 1” hail (quarter) 1.75” hail (golf ball) 2.75” hail (baseball)* Flash Flood Flash Flood Damage Unusually Severe Major damage with water Possible Damage* rising to levels rarely seen* Tornado Tornado Indicated or High confidence in Observed damaging tornado Observed* damaging tornado* near population center.* * indicates that Wireless Emergency Alerts are activated. Ensure that you enable wireless emergency alerts on your mobile device and tell your friends and family to do the same! For more info, visit: weather.gov/wrn/wea NWS Columbia, SC—Spring/Summer 2021 Page 4 Missing Out on April Showers by Chris Rohrbach - Meteorologist f the old adage holds true, anyone I looking forward to flowers this May was surely disappointed. The past April was one of the driest on record for the Midlands of South Carolina. At the Co- lumbia Metropolitan Airport the monthly rainfall total was 0.80 inches, about 30% of normal amounts. Perhaps worse off were the eastern Midlands and the Pee Dee. The figure on the right shows the percent of normal rainfall across the re- gion for April 2021. Virtually all of cen- tral SC experienced below normal amounts. But Sumter, SC fared worse than most areas. The Cooperative Ob- server (COOP) station measured only 0.30 inches of rain for the month which is less than 10% of the station's normal Percent Normal Precipitation during April 2021. amount. This is the lowest monthly rain- Rainfall Data is Estimated. fall total for any month since November of 2007 at the Sumter station. The lack of rain brought South Carolina into the D0, or abnormally dry, category on the US Drought Monitor which is a group of agencies and organizations which map areas of drought in the United States. The group says that historically the D0 category can cause stunted crop growth, early irrigation and an increase in brush fires. In fact, on April 21st in Aiken county a wildfire began during the afternoon and burned about 90 acres and forced evacuations in a nearby subdivision. Two days in April carried the vast majority of the rainfall for the month. April 10th and 24th recorded 0.10 inches and 0.67 inches respectively at the Columbia Metro Airport. This accounted for a little over 96% of the monthly total. April 2021 was tied for the 8th driest April since precipitation records began for CAE. NWS Columbia, SC—Spring/Summer 2021 Page 5 Updated Climate “Normals” by Nicole Steeves and Dan Miller - Meteorologists he sprinklers trying to revive the brown T lawn that was perfectly green just last year. The seemingly endless pollen season. It doesn’t take much to realize we got a below average amount of rain this April. To see just how dry it was, we turn to the records. There, we can get a numerical measurement of exactly how far off from average we were. But how is that average calculated? A climate “normal” is a 30 year average of meteorological variables like precipitation and temperature at a given location. 30 years of data generally offsets the extremes and variations, such as ENSO (El Nino-Southern Oscillation), that we might see from one year to the next. Every ten years, these normals are updated to include data from the previous ten years. The National Center for Environmental Information (NCEI) released the new set of 30- year climatological normals for the US in May, using weather observations taken during the 30 year period from 1991 through 2020. This includes new normal daily high and low temperatures and precipitation amounts, along with monthly and annual normals of temperature and precipitation. The previous dataset we were using covered the period 1981-2010. The next set of 30-year normals will cover the period 2001-2030, and will be updated and released in 2031. The 30-year time period standard for climatological normals was established by the World Meteorological Organization (WMO) early in the 20th century. The reason that a 30-year period was used was due to the fact that, at that time, many locations around the world only had around 30 years of continuous meteorological observations. The normals are used to compare climate from location to location, and also to compare changes in time at any given location. Note that daily/ monthly record highs/lows and precipitation amounts still use the full dataset for the period of record of continuous observations.

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